Introduction

A MAC protocol is used to address resolving potential contention and collision when the communication medium is used. Many MAC protocols have been proposed for wireless networks (e.g., Bharghavan et al., 1994; Fullmer, 1998; Fullmer and Garcia-Luna-Aceves, 1995; Garcia-Luna-Aceves and Tzamaloukas, 1999; Garcias and Garcia-Luna-Aceves, 1996; Lin and Gerla, 1997b; Lu et al., 1999; Vaidya et al., 2000), which often assume a common channel shared by mobile hosts.

Contention-Based MAC

The MAC protocol is essential for stations that share a common broadcast channel. CSMA protocols (Kleinrock and Tobagi, 1975) have been used in a number of packetradio networks in the past (Leiner et al., 1987). These protocols attempt to prevent a station from transmitting simultaneously with other stations within its transmitting range by requiring each station to listen to the channel before transmitting. Unfortunately, the performance of the CSMA protocol suffers from hidden-terminal problems and exposed-terminal problems substantially. To remedy these problems, several approaches (Bambos and Kandukuri, 2000; Bharghavan et al., 1994; Colvin, 1983; Fullmer and Garcia-Luna-Aceves, 1995; Karn, 1990; Monks et al., 2001) were proposed in the literature. Karn (1990) proposed a protocol called MACA that attempts to detect collision at the receiver by establishing a request-response dialog between senders and intended receivers. When a sending station wants to transmit, it sends an RTS to the receiver, which responds with a CTS if it receives the RTS correctly.